This invention relates generally to audio video signal generators and relates particularly to those utilized for music or music tone generation for use in small educational and entertainment devices such as those found in hand-held or desk-top units.
The recent rise in popularity of small electronic hand-held, desk-top, and television player type educational and entertainment devices is well known. In large part this popularity increase occurred as a result of substantial advancements in the semiconductor processing and digital electronic arts whereby the development of the microprocessor circuit evolved. In essence, a microprocessor provides a miniaturized computer capable of performing significant computational and processing routines which can be used in a variety of small, easy to use, and relatively inexpensive low power packages. Initially such devices were relatively low in sophistication. However, as development continued the implimentation of complicated display systems and arrays and challenge in the operation of such devices. In the course of development of devices having greater and greater player and consumer appeal, developers of such educational and entertainment devices included sound generating systems to augment display. Initially these sound systems were nothing more than circuits capable of producing "beeps" of different tones used to indicate success or failure of the player or pupil. However, as the above mentioned sophistication increased, the sound portion of educational routines and game play also increased to a point where educational devices and games which are microprocessor driven frequently include actual music routines and in some instances great effort is exercised to produce a desired character and voice of sound produced in addition to the tonal differences accompanying different notes.
As mentioned, the heart of these educational and entertainment devices is the microprocessor digital electronics system. Therefore, economics mandates that music and tone generators used therein be as compatible with the digital system as possible. The need for digitally driven music producing systems has prompted practioners in the art to design and develop numerous types of sound systems for combination and cooperation with digital electronic systems. While many of the previously developed presently used sound systems provide sufficient tonal flexibility and voice capability to satisfy the teaching and play needs of such educational and entertainment devices, most systems are expensive. The need remains, therefore, for a digitally-driven, low-cost, easy-to-fabricate, audio effects generating system.